I am trying to implement the [large collection example](https://diogofcunha.github.io/react-virtualized-tree/#/examples/large-collection) using a functional component. Having difficulty with basic imports eg: `import TreeState from 'react-virtualized-tree/TreeState'` If I do `import { TreeState } from 'react-virtualized-tree'`, I get the following error: ``` Cannot read property 'createFromTree' of undefined class LargeCollection extends Component { state = { nodes: TreeState.createFromTree(Nodes), ^ }; ```